Retrieve Source IP and Port
Hi!
I want to write a client/server program. The client should send a udp packet and the server should answer the packet telling the client from which source ip address and port he received the packet.
Is it somehow possible with java to retrieve the address/port a packet came from ?
Thanks, Jack
That's what I was looking for.
Thanks
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Finding out the source ip and port of an incoming Upacket
Hi, does anybody know how to find out the source ip address and port of a udp packet coming into an rtp session based on a NewParticipantEvent or a NewReceivedStreamEvent? I would really appreciate any reply...
thanksThe only proper solution is the one pointed out by ejp :
1) Accept new connection with ServerSocket, store the newly created Socket in a collection of some sort.
2) Map the collection in a way that's suitable to your application. Then when you need to send something to client X you simply look up which Socket instance has been accepted/created for said client and use the in/out streams to transfer data. -
Retrieve the Hostname and port of the server
Hi,
How can i from my webdynpro code get the hostname and the port of the server in which the program is running?
Thanks in Advance!
JoHi Jo,
I think so u can retrive using this URL:
http://<host name>:<port number>/webdynpro/dispatcher/local/<Web Dynpro project>/<name of Web Dynpro application>.
check on to this link for more details:
http://help.sap.com/saphelp_erp2005/helpdata/en/7d/09044132bcef23e10000000a155106/frameset.htm
Hope tihs helps u,
Regards,
Nagarajan. -
Logon Error:Could not retrieve the source file for Port "Main"
Hi All,
We have a port which is blocked due to structural exceptions.When i try to connect to the Exceptions folder
"Main[Exceptions]" the import manager throws an error "Logon Error:Could not retrieve the source file for port "Main".
Any help greatly appreciatedHi ,
Thanks for your reply.
This is what I see in the log file in the exceptions folder
These are the line I see almost to the end of the log file before they complete field mappings,value addings
<Failure ts="2008/07/22 00:10:48.326 GMT" tid="1286" entry-no="9114" operation="Create lookups" rc="0x80000001">Illegal value for parameter</Failure>
<Timer ts="2008/07/22 00:10:48.327 GMT" tid="1286" entry-no="9115" name="Import Lookup" total="0.040819">1</Timer>
<Trace ts="2008/07/22 00:10:48.327 GMT" tid="1286" entry-no="9116">Import of Lookup Failed.</Trace>
But when I open the same source xml file after downloading to my local folder from Exceptions Structural folder and load manually using IM i get the status as "Ready to import".
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ACE: Can I loadbalance based on client Source IP/and client tcp source port?
We recently migrated serving a client from being thick client at the desktop to being served via a citrix farm. Prior to the migration the clients came from about 5000 unique source IP's to their VIP, now they come from only 31 unique source IP's from the citrix servers in the farm. A citrix server can host 400 client sessions, since the default action of the ACE is to loadbalance based on source IP's, the ACE is sending up to 400 sessions from one citrix server to 1 real server in the farm. Is there anyway I can loadbalance based on client source IP and tcp source port so the ACE views the 400 sessions from one citrix server as unique sessions? The application does not require persistence.
Hello,
Yes, you can configure a "Sticky Layer 4 Payload" as descirbed on this Link:
http://www.cisco.com/en/US/docs/interfaces_modules/services_modules/ace/vA2_3_0/command/reference/sticky.html#wp1039276
Unfrotunately I do not have any working example. You must calculate the right values for the Offset and the Length to configure.
Regards Jean-Marc -
How to use "Add from POM" to add source path and docpath?
Hi
My team is developing multiple projects with JDeveloper 11gr2.
We share libraries and sources between team members using maven extension for JDeveloper.
We deploy class jar, source jar and javadoc jar to repository.
The project pom has some dependency defined as below
<dependency>
<groupId>com.example</groupId>
<artifactId>CommonClient</artifactId>
<version>0.0.1-SNAPSHOT</version>
<type>jar</type>
<scope>compile</scope>
</dependency>
We use ProjectProperties->Mave->Dependencies->Add from POM button to add dependecies to Project.
The problem is that the class jar is added to the classpath but the source jar and javadoc jar are not.
As a result, Team members cannot see the javadoc in code editor.
Configure IDE libraries is an option but does not work well with maven.
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Thank you!Hi ,
Sample code snippet for GET_RELATED_CONTENT is as follows :
dataBinder.putLocal("IdcService", "GET_RELATED_CONTENT");
dataBinder.putLocal("dSource","CS");
dataBinder.putLocal("dID","3202");
dataBinder.putLocal("dLinkTypeID","1");
serializer.serializeBinder (System.out, dataBinder);
// Send the request to Content Server
ServiceResponse response = idcClient.sendRequest(userContext,dataBinder);
// Get the data binder for the response from Content Server
DataBinder responseData = response.getResponseAsBinder();
// Write the response data binder to stdout
serializer.serializeBinder (System.out, responseData);
// Retrieve the SearchResults ResultSet from the response
DataResultSet resultSet = responseData.getResultSet("RelatedContent");
// Iterate over the ResultSet, retrieve properties from the content items
for (DataObject dataObject : resultSet.getRows ()) {
System.out.println ("Related ContentID is : " + dataObject.get ("dDocName") );
Point to note is :
dLinkTypeID is set to 1 . Reason being that the rendition related content is used to link items . So looking for those related items which are as Renditions .
This value would be as follows :
dLinkTypeID Related content type
1 Rendition
2 Supersedes
3 Has Supporting content
4 Cross References
2 more sub types are :
Supports - dLinkTypeID=3 and extraparameter is isGetParents=1
Cross Referenced By - dLinkTypeID=4 and extraparameter is isGetParents=1
Hope this helps .
Thanks,
Srinath -
Are "Back to my MAC" and "Port Forwarding" mutually exclusive?
I have been using APExtreme and Port Forwarding successfully for several weeks now. The PF is to allow access to game players on a PC which acts as a server on the web. All Good.
One more thing, I have a ISP provided wireless modem/router to talk to the cable and the world. It seems to work either bridged or un-bridged.
I have disabled the wireless on the ISP's modem/router. (Actually the ISP's device doesn't hold a candle to the APE.)
Still all good.
So the firewall is on in the APExtreme and none on the modem router, and I have a port defined for my gamers to get access to my server in the APExtreme.
I now want to implement Back to my MAC on my MBP and my other Apple devices. I believe these use iCloud for which I have an account and it seems to be working well with my iPhone.
In Properties, when I select BtmM, iCloud says communications will be slow if I have port forwarding on. Also I will not be able to use the router function in my Modem/router.
I'd really like to have the modem/router firewall up, and do the port forwarding there, but the BtmM will likely not get through.
So what does anyone suggest?
Can I use BtmM and port forwarding without too much degradation?
Please advise.
Thanks
BarryTo best answer your question on whether the two are "mutually exclusive," let take a look at how Back to My Mac (BTMM) basically works.
BTMM - General Requirements
OS X Leopard 10.7.3+
Active iCloud account. Each Mac & the AirPort router, that will be relying on BTMM, needs to be configured with the same account.
A publicly reachable IP address for your router.
A router that supports either NAT-PMP or UPnP. For AirPorts, be sure it is running 7.6.1+ firmware.
BTMM uses TCP port 5354 and UDP ports 4500 & 5353 for communications.
BTMM - Basic Communication Flow
For a computer connected to the Internet via a router, BTMM "asks" the router for its configuration information. For a router, like your AirPort, that uses NAT-PMP, BTMM will ask the router to assign arbitrary public ports. In turn, the router will provide these port assignments (& the router's Public IP address) back to BTMM.
BTMM then sends this information to the iCloud account. In background iCloud updates a special set of DNS entries to be used by BTMM. These entries are then made available to all BTMM clients using your iCloud account. When a computer, with BTMM enabled, uses your iCloud credentials, it automatically retrieves a list of all other computers/routers that are registered with the same account. All these devices should then appear under the SHARED section of the Finder.
When attempting to connect to a remote computer (or router), BTMM creates a secure connection to that remote device using the information from the iCloud account.
Once the connection is established, the devices can then communicate with each other.
So potentially, unless you are using Port Mapping for any of the ports BTMM uses, they should not conflict. -
I have an existing policy-map with vip and port 80. Now I need to do:
1. Match pool of ip address and url /abc then redirect to url /abc1
2. If url is ok but ip is out of the pool then redirect to url /abc2
It's probably possible to achieve but I have problem with mixing class maps (L4 and L7). Please advice how to do it.
Thank you.HI Kamil,
Something like below. Please try and let me know if it helps.
rserver redirect red
webhost-redirection www.abc1.com
inservice
rserver redirect red1
webhost-redirection www.abc2.com
inservice
serverfarm redirect red
rserver red
inservice
serverfarm redirect red1
rserver red1
inservice
class-map type http loadbalance match-all url
2 match http url abc
4 match source-address 2.2.2.2 255.255.255.0
class-map type http loadbalance match-all url1
2 match http url abc
policy-map type loadbalance first-match url
class url
serverfarm red
class url1
serverfarm red1
class class-default
serverfarm xxxx
Regards,
Kanwal
Note: Please mark answers if they are helpful -
How to Create an R/3 source system and load data from there
Hello All,
Till now I have only worked with Flat files. I want to create an R/3 source system and extract data from there on to my Info Providers.
Does anyone has detailed steps for that. I am using BW 3.5 system
Thanks n Regards,
Abhishek1. Type Transaction WE30. Check iDoc types
2. Type Transaction SM59. Maintain RFC destinations
a.) Open the RFC Destinations. b.) Find your Source System and double click on it. c.) Technical setting should contain information regarding yoursource system d.) Logon Information should contain source system client and name & password for you remote logon. We use RFC_SAB for BW logon to R/3 and RFC_AAE for R/3 logon to BW. Password for both is always xxxxxxx. e.) Execute your 'Test Connection' & 'Remote Logon'. You should NOT be prompted for a password, if you are then the logon info is incorrect. f.) Repeat above to verify RFCs for other systems (CRM etc)
3. Type Transaction WE21. iDoc Processing Ports.
a.) Select 'Ports' and then 'Transactional RFC'. b.) Click on the Port # for you source system. c.) Verify description & SAP R/3 version.(BW 2.1C should be release 4.x) d.) RFC Destination should be one created in SM59. If non-existent then create one
4. Type Transaction SE16. Data browser (for R/3  BW Connections)
5. Type Transaction SM30. Msg Types & Assignment to iDocs
Enter 'EDIMSG' in the Table/View field. Click on the 'Enter Conditions' option for Restrict Data Range. Click 'Maintain'. Select Message Type. Then enter 'RSSEND' in "From' field. Verify that the Basic Type matches what is in your RSBASIDOCtable for each of your connections. If any are missing any entries you must create them as follows: Create another session and type Transaction WE30. Enter IDoc Type (ZSBAXXX) in Obj. Name field (Suggestion: Start new type with 'ZS' + Transfer Structure Prefix + (3)#'s) Select Create. Select "Create from Copy'. Enter 'RSSEND" in 'Copy From' field Enter Description (i.e. IDoc Type for BW Development) Execute (Green Check). Repeat for other missingentries.
6. Go to the SM30 main screen. Clients Overview
Enter 'T000' in the Table/View field. Click 'Maintain'. Verify correct Client and Description. If incorrect enter.
8. On BW Type Transaction WE20. Partner Profiles
9. On R/3 Type Transaction WE20. Partner Profiles
10. Check all is correct -
IP DHCP snooping, IP source Guard, and DIA
Hi All,
I have Configured DHCP snooping and IP source guard and Dynamic arp inspection on my 3560 and 3750 Network Switches,
on both of them I'm facing that issue. (the printers and access points are configured to get ip addresses via DHCP), but when the lease time expires, they don't get ip addresses, and become unreacheable.
while all other clients get thier ip addresses normally
below you can find the Configuration configuration
ip dhcp snooping vlan 98,105,111
no ip dhcp snooping information option
ip dhcp snooping database flash:dhcpsnooping
ip dhcp snooping database write-delay 15
ip dhcp snooping
ip arp inspection vlan 98,105,111
ip verify trust on all access ports including printers and access point ports
all access ports are DHCP snooping untrusted
also when I create a static dhcp snooping binding record for these devices on the switch it resolves the Issue, but when I reload the switch it's removed automatically.
any resolution will be much appreciated.
regards,
Mahercheck the following link for configuration of DHCP snooping
http://packetlife.net/blog/2010/aug/18/dhcp-snooping-and-dynamic-arp-inspection/
http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst6500/ios/12-2SX/configuration/guide/book/snoodhcp.html -
Get the source coding and the interface of a from routine (4.6C)
Hello,
I am looking for a way to get the source coding and the interface of a Form routine. Having a look at the functionality used in SE80, I found the function module RS_SEARCH_FORM.
By specifying the following parameters:
Include Name: i_incl
Main program: i_mainprogram
Form routine name i_objectname
Object Type for Form routine: i_objecttype
you receive the "pattern", which is being generated by using the drag and drop
functionality for Form routines in SE80. For example:
PERFORM test
USING
a.
In addition to this, I am looking for a way to get the source coding and the interface for a form routine in a 4.6C system.
The mentioned function module has a tables parameter called i_source but I didn't find out how to execute it in order receive the source code.
It would be great if you could help me to solve this issue.
Best regards,
FabianHi,
the only idea I have is to scan the source code for the form routine in order to retrieve the needed information. It would be great to have a standardized function module, which provides this functionality.
Regards,
Fabian -
API method to query multicast address and port of a cluster
I am new to Tangosol and I'm looking to write a quick Java dashboard that will display current information on our cluster, such as the clustername and the multicast address and port that is being used. Looking at the API I've found the Cluster object and I'm able to get the memeberset and the clustername.But I have not been able to find a way to query the multicast address and port being used by the cluster.
Any help or links would be appreciated.
Thanks,
LenHi Len,
All this information could be retrieved via JMX. Please see this Wiki page. Detailed documentation about the semantics of all exposed attributes and method could be found in the Javadoc for the <a href ="http://tinyurl.com/r75sy">Registry interface</a>.
Regards,
Gene -
Can javamail use windows default outgoing smtp mail server and port?
how can i use windows default outgoing smtp service and port from javamail? is it possible to retrieve this info or just instruct javamail to use default?
thanksWindows doesn't have a default SMTP server. However if you have something like Outlook or Outlook Express or Eudora or Netscape Mail or whatever set up on your Windows box, you will have already told it what SMTP server it should connect to.
That information would be in the Windows registry, or in the config file of whatever e-mail client you already have set up. However it's probably easier to just have your application ask for the SMTP server's name again rather than trying to find where some other application stashed it. -
Hi Guys,
Iam seeing above issue on two of my switches connected to core switch ....i know there are quite of few discussion open on same issue but mine is diff....
i see same issue on two switches connected via core swicth on same vlan ( 112)....when i do mac address lookup it says the mac thats generating this error is invalid so cant track the source of this mac....also just saw on topoogy change notification on core traced it back to originating switch which is also generating this error but dnt see any change on the switch that is generated topology change notification....prob is vlan 112 all interface on both switches conected via core are generating this message so five interfaces each .....any expert advise on how to approach it as i cant get to source port generating this as nearly five ports in vlan 112 on bloth switches generating this error. thanks
Apr 15 15:56:08: %SW_MATM-4-MACFLAP_NOTIF: Host 00ff.ffff.ffff in vlan 112 is flapping between port Fa3/0/46 and port Gi3/0/1
Apr 15 15:56:50: %SW_MATM-4-MACFLAP_NOTIF: Host 00ff.ffff.ffff in vlan 112 is flapping between port Fa2/0/46 and port Gi3/0/1
Apr 15 15:56:51: %SW_MATM-4-MACFLAP_NOTIF: Host 00ff.ffff.ffff in vlan 112 is flapping between port Fa3/0/46 and port Gi3/0/1
Apr 15 15:58:29: %SW_MATM-4-MACFLAP_NOTIF: Host 00ff.ffff.ffff in vlan 112 is flapping between port Fa2/0/46 and port Gi3/0/1
Apr 15 15:59:27: %SW_MATM-4-MACFLAP_NOTIF: Host 00ff.ffff.ffff in vlan 112 is flapping between port Gi3/0/1 and port Fa2/0/46
Apr 15 15:59:45: %SW_MATM-4-MACFLAP_NOTIF: Host 00ff.ffff.ffff in vlan 112 is flapping between port Fa2/0/46 and port Gi3/0/1
Apr 15 16:00:14: %SW_MATM-4-MACFLAP_NOTIF: Host 00ff.ffff.ffff in vlan 112 is flapping between port Gi3/0/1 and port Fa3/0/46
Apr 15 16:00:36: %SW_MATM-4-MACFLAP_NOTIF: Host 00ff.ffff.ffff in vlan 112 is flapping between port Fa2/0/46 and port Gi3/0/1
Apr 15 16:02:40: %SW_MATM-4-MACFLAP_NOTIF: Host 00ff.ffff.ffff in vlan 112 is flapping between port Fa3/0/46 and port Gi3/0/1
Apr 15 16:03:22: %SW_MATM-4-MACFLAP_NOTIF: Host 00ff.ffff.ffff in vlan 112 is flapping between port Fa3/0/46 and port Gi3/0/1
Apr 15 16:03:31: %SW_MATM-4-MACFLAP_NOTIF: Host 00ff.ffff.ffff in vlan 112 is flapping between port Gi3/0/1 and port Fa2/0/46
Apr 15 16:04:03: %SW_MATM-4-MACFLAP_NOTIF: Host 00ff.ffff.ffff in vlan 112 is flapping between port Fa3/0/46 and port Gi3/0/1
Apr 15 16:04:34: %SW_MATM-4-MACFLAP_NOTIF: Host 00ff.ffff.ffff in vlan 112 is flapping between port Fa2/0/46 and port Gi3/0/1
Apr 15 16:04:41: %SW_MATM-4-MACFLAP_NOTIF: Host 00ff.ffff.ffff in vlan 112 is flapping between port Gi3/0/1 and port Fa2/0/46
Apr 15 16:05:05: %SW_MATM-4-MACFLAP_NOTIF: Host 00ff.ffff.ffff in vlan 112 is flapping between port Fa2/0/46 and port Gi3/0/1
Apr 15 16:05:13: %SW_MATM-4-MACFLAP_NOTIF: Host 00ff.ffff.ffff in vlan 112 is flapping between port Gi3/0/1 and port Fa3/0/46
sh spanning-tree vlan 112
VLAN0112
Spanning tree enabled protocol rstp
Root ID Priority 8192
Address 001e.13c1.5a70
Cost 3004
Port 109 (GigabitEthernet3/0/1)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 49264 (priority 49152 sys-id-ext 112)
Address 001f.261c.1d80
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300
UplinkFast enabled but inactive in rapid-pvst mode
Interface Role Sts Cost Prio.Nbr Type
Fa2/0/46 Desg FWD 3019 128.104 P2p
Fa1/0/46 Desg FWD 3019 128.50 P2p
Gi3/0/1 Root FWD 3004 128.109 P2p
Fa3/0/46 Desg FWD 3019 128.158 P2p
Fa3/0/47 Desg FWD 3100 128.159 P2p
Fa3/0/48 Desg FWD 3019 128.160 P2pASAK Mohammed,
There are lots of thread discussing about this, you should do a search before creating a new post.
Anyway, this is how you approach these types of flapping:
1. Is the the given MAC flapping in the log flapping only 1 time or you see it multiple times over a reasonobly short time?
If you see it only once or once every 2-3 hours this might be not an issue worth being investigated. Sporadic one time flapping are expected in L2 broadcast domain.
If you see it often continue to step 2.
2. Identify and locate the flapping mac in vlan 125: 3270.990a.a504
Is the mac of a dual-homes server using some kind of load balancing algorithm (active/active) for which the same address is used from both NICs?
If yes, the message is not and issue but just an indication. Fix this type of LB (make it active/standby or make sure the server uses 2 different mac addresses, one per NIC) or if it is not possible leave it like this.
3. Is the MAC a the wireless NIC of a PC?
Make sure that the user was not moving from one AP to another (flapping is normal in this case)
4.
See if you have increasing TCN's and check if they are coming from the same interface.
From this point on you keep on troubleshooting STP until you find the offending link (likely going up and down) or the switch. You also need to check if STP in vlan112 is coherent with the actual L2 topology you have.
=====================================================
2- Some more details information which might be helpfull to you.
http://www.cisco.com/en/US/products/hw/switches/ps663/products_tech_note09186a
00801434de.shtml#subtopic1k
Problem
The switch generates %SYS-3-P2_ERROR: Host xx:xx:xx:xx:xx:xx is flapping
between ports? messages, where xx:xx:xx:xx:xx:xx is a MAC address.
Description
This example shows the console output that you see when this error occurs:
%SYS-4-P2_WARN: 1/Host 00:50:0f:20:08:00 is flapping between port 1/2 and port
4/39
Use the steps and guidelines in this section in order to understand and
troubleshoot the cause of this error message.
The message indicates that your Catalyst 4500/4000 switch has learned a MAC
address that already exists in the content-addressable memory (CAM) table, on
a port other than the original one. This behavior repeatedly occurs over short
periods of time, which means that there is address flapping between ports..
If the message appears for multiple MAC addresses, the behavior is not normal.
This behavior indicates a possible network problem because the MAC addresses
move quickly from one port to another port before the default aging time. The
problem can be looping traffic on the network. Typical symptoms include:
· High CPU utilization
· Slow traffic throughout the network
· High backplane utilization on the switch
For information on how to identify and troubleshoot issues with spanning tree,
refer to Spanning Tree Protocol Problems and Related Design Considerations
<http://www.cisco.com/en/US/tech/tk389/tk621/technologies_tech_note09186a00800
951ac.shtml> .
If the error message appears for one or two MAC addresses, locate these MAC
addresses in order to determine the cause. Issue the show cam mac_addr command
in order to identify from where these MAC addresses have been learned. In this
command, mac_addr is the MAC address that the error reports as flapping.
After you determine between which ports this MAC address is flapping, track
down the MAC address. Connect to the intermediate devices between your
Catalyst 4500/4000 and the device that has the problem MAC address. Do this
until you are able to identify the source and how this device connects to the
network.
Note: Because the MAC address is flapping between two ports, track down both
of the paths.
This example shows how to track both of the paths from which this MAC address
has been learned:
Note: Assume that you have received this message and you have begun to
investigate it.
%SYS-4-P2_WARN: 1/Host 00:50:0f:20:08:00 is flapping between port 1/2 and port
4/39
In order to track down how this MAC address was learned from both ports,
complete these steps:
1. Consider port 1/2 first, and issue the show cam dynamic 1/2 command.
If you see the MAC address 00:50:0f:20:08:00 in the list of the MAC addresses
that have been learned on this port, determine if this is a single host that
is connected or if there are multiple hosts that are registered on that port.
2. On the basis of whether there is a single or multiple hosts,
investigate the device:
o If there is a single host (00:50:0f:20:08:00) that is connected, check the
other port that is registered and see if the host is dually attached to the
switch.
In this example, the other port is port 4/39.
o If the host has connections to other devices that can eventually lead back
to this switch, try to track down the intermediate devices.
With Cisco devices, issue the show cdp neighbors mod/port detail command. The
output provides information about intermediate devices.
Here is sample output:
Cat4K> (enable) show cdp neighbors 1/2 detail
Port (Our Port): 1/2
Device-ID: brigitte
Device Addresses:
IP Address: 172.16.1.1
Novell address: aa.0
Holdtime: 171 sec
Capabilities: ROUTER
Version:
Cisco Internetwork Operating System Software
IOS (tm) 2500 Software (C2500-JS-L), Version 12.0(7)T, RELEASE SOFTWARE (fc2)
Copyright (c) 1986-1999 by cisco Systems, Inc.
Compiled Mon 06-DEC-99 17:10 by phanguye
Platform: cisco 2500
Port-ID (Port on Neighbors's Device): Ethernet0
VTP Management Domain: unknown
Native VLAN: unknown
Duplex: half
System Name: unknown
System Object ID: unknown
Management Addresses: unknown
Physical Location: unknown
Cat4K> (enable)
3. Establish a Telnet session with the device and follow the path of the
MAC address.
In this example, the IP address is 172.16.1.1.
Repeat the procedure for all MAC addresses that the error message reports as
flapping.
4. Create a simple diagram of the source device with that MAC address and
of the physical connections (the Catalyst 4500/4000 ports) from which and to
which this MAC address is flapping.
The diagram enables you to determine if this is a valid port and path for your
network layout.
If you verify that both ports on which the MAC address is flapping provide a
path toward that network node, there is a possibility that you have a
spanning-tree failure issue. Refer to Spanning Tree Protocol Problems and
Related Design Considerations
<http://www.cisco.com/en/US/tech/tk389/tk621/technologies_tech_note09186a00800
951ac.shtml> in order to isolate and troubleshoot this loop.
In large networks in which multiple hosts from multiple vendors are
interconnected, difficulty arises as you try to track down the host with use
of just the MAC address. Use the search utility for the IEEE OUI and
Company_id Assignments <http://standards.ieee.org/regauth/oui/index.shtml> in
order to track down these MAC addresses. This list is the front end of the
database where IEEE has registered all MAC addresses that have been assigned
to all vendors. Enter the first three octets of the MAC address in the Search
for: field of this page in order to find the vendor that is associated with
this device. The first three octets in the example are 00:50:0f.
These are other issues that can cause this message to appear:
· Server NIC redundancy problem?There is a server with a dual-attached
NIC that misbehaves and does not follow the standards. The server uses the
same MAC address for both ports that connect to the same switch.
· Hot Standby Router Protocol (HSRP) flapping?Flapping HSRP can cause
these messages to appear in the Supervisor Engine console. If you notice that
HSRP implementation in your network is unstable, refer to Understanding and
Troubleshooting HSRP Problems in Catalyst Switch Networks
<http://www.cisco.com/en/US/tech/tk648/tk362/technologies_tech_note09186a00800
94afd.shtml> in order to resolve the problem.
· EtherChannel misconfiguration?A misconfigured EtherChannel connection
can also cause these symptoms. If ports that the flapping message reports are
members of the same channel group, check your EtherChannel configuration and
refer to Understanding EtherChannel Load Balancing and Redundancy on Catalyst
Switches
<http://www.cisco.com/en/US/tech/tk389/tk213/technologies_tech_note09186a00800
94714.shtml> in order to troubleshoot the configuration.
· Host reflects packets back onto the network?The reflection of packets
back onto the network by a host can also cause flapping. Typically, the root
cause of this packet reflection is a broken NIC or any failure of the physical
interface of the host that is connected to the port.
If the reflection of packets by the host is your root cause, obtain a sniffer
trace and examine the traffic that goes to and from the ports on which the
messages have appeared. If a host reflects packets, you typically see
duplicate packets in the trace. The duplicate packets are a possible symptom
of this flapping of the MAC address.
Refer to Configuring SPAN and RSPAN
<http://www.cisco.com/en/US/docs/switches/lan/catalyst4000/6.3and6.4/configura
tion/guide/span.html> for details on how to configure a port for use with a
sniffer.
· Software or hardware defect?If you have tried to troubleshoot the
flapping message with the instructions in this section but you still notice
the issue, seek further assistance from Cisco Technical Support
<http://www.cisco.com/en/US/support/tsd_cisco_worldwide_contacts.html> . Be
sure to mention and provide documentation of the information that you have
collected while you followed the steps. This information makes further
troubleshooting quicker and more efficient.
HTH
REgards
Inayath
*Plz rate all usefull posts. -
Hi all ,
we have a network with CORE4507 access 2960x24port+4portSFP
CORE configured to allowed vlan all till access switch SFP interface Gi1/0/27 when i show log to switch i found error below.
\%SW_MATM-4-MACFLAP_NOTIF: Host 4025.c225.d9f0 in vlan 16 is flapping between port Gi1/0/27 and port Gi1/0/12
In access switch port Gi1/0/12 and port Gi1/0/24 is configured as trunk and WAP121 wirelessAP is connected tow SSID,s are configured SSID1=VLAN 10 SSID2=VLAN16
interface GigabitEthernet1/0/12
switchport trunk allowed vlan 10,16
switchport mode trunk
interface GigabitEthernet1/0/24
switchport trunk allowed vlan 10,16
switchport mode trunk
Any Help
RegardsHello Akash,
Thanks for repley port 1/0/27 is configured as trunk and allowed Vlan All
interface GigabitEthernet1/0/27
switchport mode trunk
this is sh cdp ne
V35#sh cdp neighbors
Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
S - Switch, H - Host, I - IGMP, r - Repeater, P - Phone,
D - Remote, C - CVTA, M - Two-port Mac Relay
Device ID Local Intrfce Holdtme Capability Platform Port ID
CORE1 Gig 1/0/27 176 R S I WS-C4507R Gig 1/23
Regards
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